Diisopinocampheylborane chloride

In the area of ion sensing, cation recognition by electrodes containing functionalized redox-active polymers has been an area of considerable interest. Fabre and co-workers have reported the development of a boronate-functionalized polypyrrole as a fluoride anion-responsive electroactive polymer film. The electropolymerizable polypyrrole precursor (11) (Fig. 11) was synthesized by the hydroboration reaction of l-(phenylsulfonyl)-3-vinylpyrrole with diisopinocampheylborane followed by treatment with pinacol and the deprotection of the pyrrole ring.33 The same methodology was utilized for the production of several electropolymerizable aromatic compounds (of pyrrole (12) (Fig. 11), thiophene (13 and 14) (Fig. 11), and aniline) bearing boronic acid and boronate substituents as precursors of fluoride- and/or chloride-responsive conjugated polymer.34... 

Transformation of ketones to alcohols has been accomplished by many hydrides and complex hydrides by lithium aluminum hydride [55], by magnesium aluminum hydride [89], by lithium tris tert-butoxy)aluminum hydride [575], by dichloroalane prepared from lithium aluminum hydride and aluminum chloride [816], by lithium borohydride [750], by lithium triethylboro-hydride [100], by sodium borohydride [751,817], by sodium trimethoxyborohy-dride [99], by tetrabutylammonium borohydride [771] and cyanoborohydride [757], by chiral diisopinocampheylborane (yields 72-78%, optical purity 13-37%) [575], by dibutyl- and diphenylstannane [114], tributylstanrume [756] and others Procedure 21, p. 209). 

The hydroboration of acetylenes (3) with diisopinocampheylborane (IpC)2BH in THF led after refunctionalisation and transesterification to the olefins (4a, b, c) isolated in good yields. Monooxidation with mCpBA led to the sulfoxide (4d) whereas the sulfone (4e) was obtained with two equivalents of mCpBA. The same sulfone (4e) could also be obtained in an excellent overall yield by radical addition of phenylsulfonyl iodide to the pinacol ester of vinylboronic acid followed by a dehydroiodination in the presence of Et2N (87 % overall yield). The carboxylic ester (4a) could be transformed into the corresponding carboxylic acid (4f) (79 % yield) 11 which led to the acid chloride (4g) by treatment with freshly distilled thionyl chloride at 0°C (91 % yield), p-keto vinylboronates are easily accessible by oxidation of the corresponding protected allylic alcohol according to the following scheme ... 

Resolution 3t3-Acetoxy-A. etienic add. T-Acid from a tetranitrofluorenone and an optically active hydroxylamine. i><—>Butane-2,3-diol. L.(+)-Butane-2,3-dithiol. (By crystallization Silver acetate). 10-Camphorsulfonic acid. 10-Camphorsulfonyl chloride. 4-(4-Carboxy-phenyl) semicarbazide. Complex from ethylene, platinous chloride, and (- -)-l-phenyi-2-aminopropane. Debydroataetylamine. Diisopinocampheylborane. Di-p-toluoyl-o-tartrate. d- and /-u-Phenylethylamiiie. L-Pyrrolidonecarboxylic add. a-(2,4,S,7-Tetianitro-9-fluorenyl-ideneaminooxy)-propionic acids. 

Method B 100 mmol of diisopinocampheylborane, prepared as above, are suspended in 50 mL of Et20 at 0SC, and hydrogen chloride gas is passed through the solution until all of the solid dissolves. Removal of the solvent provides the reagent as a white powder mp54-55cC. 

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